In general, for clad materials for heat exchangers used for intercoolers, oil coolers, radiators, condensers, evaporators and heater cores or the like of vehicles, rolled skin materials are used. For example, a conventional method for manufacturing a typical clad material for heat exchangers is described in Patent Document 1, as follows: At first, an aluminum alloy for core material and an aluminum alloy for skin material (sacrificial anode material and filler material in Patent Document 1) are melted (hereafter referred to as “dissolved”) and cast by the continuous casting, and a heat treatment for homogenization is performed as necessary. Aluminum alloy ingots for skin material are hot-rolled so as to have a predetermined thickness, respectively (see S11a and S11b in FIG. 14: Note that a heat treatment for homogenization is described as “homogenization heat”). Subsequently, the aluminum alloy ingot for core material and the hot-rolled plates for skin material (member for skin material) are superposed one on another (see S12 in FIG. 14), then are hot-rolled (clad hot-rolling: see S13 in FIG. 14) according to a common method to make a clad material.
[Patent Document 1] Japanese Unexamined Patent Application Publication No. 2005-232507 (paragraphs 0037, 0039, and 0040).